A replicated and controlled ex situ study in a research centre in Quebec, Canada(Bird & Clark 1983),found that 25 hand-reared American kestrels Falco sparverius grew more slowly than 19 parent-reared birds, also in captivity. Parent-reared birds also achieved greater body sizes than hand-reared birds (predicted weight of hand-reared birds of 119-130 g vs. 133-138 for parent-reared). Hand-reared birds were fed until sated four times a day, whilst parent birds were provided with food in excess. Survival and reproductive output were not measured in this study.